//
// Rate Findr API client, run in-page via `chromeassist -a js` so the
// browser's logged-in supporter session supplies auth (window.LH_RF.token).
//
// Synchronous XHR: chromeassist won't await a Promise.
//
// Reads the global ARGS; returns a JSON string, or { err } on failure.
//

(function () {
  var A = ARGS;

  function post(url, data) {
    data.rf_token = (window.LH_RF && window.LH_RF.token) || '';
    var body = Object.keys(data).map(function (k) {
      return encodeURIComponent(k) + '=' + encodeURIComponent(data[k]);
    }).join('&');
    var x = new XMLHttpRequest();
    x.open('POST', url, false);
    x.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
    x.send(body);
    if (x.status !== 200) throw 'HTTP ' + x.status + ' on ' + url;
    return JSON.parse(x.responseText);
  }

  function getJSON(url) {
    var x = new XMLHttpRequest();
    x.open('GET', url, false);
    x.send();
    if (x.status !== 200) throw 'HTTP ' + x.status + ' on ' + url;
    return JSON.parse(x.responseText);
  }

  function findMake(name) {
    var hit = (getJSON('/makes').makes || []).filter(function (m) {
      return m.make_name.toLowerCase() === name.toLowerCase();
    })[0];
    if (!hit) throw 'Unknown make: ' + name;
    return hit;
  }

  // One /style-data call returns every model and every trim for the make/year.
  function styleData(mk, year) {
    return post('/style-data', {
      make_code: mk.make_code,
      make_name: mk.make_name,
      model_year: year,
      country: 'us'
    });
  }

  function norm(s) {
    return String(s).toLowerCase().replace(/\s+/g, ' ').trim();
  }

  function incentives(prog) {
    var out = [];
    function pull(arr) {
      (arr || []).forEach(function (i) {
        out.push({ name: i.program_name || i.program_desc, value: i.inc_val });
      });
    }
    pull(prog.gen_incs);
    pull(prog.con_incs && prog.con_incs.cash_incs);
    pull(prog.dealer_incs);
    return out;
  }

  function rvForMiles(ld, miles) {
    var rvs = ld.rvs || [];
    var hit = rvs.filter(function (r) { return String(r.rv_mileage) === String(miles); })[0];
    return hit ? hit.rv : (rvs[0] ? rvs[0].rv : null);
  }

  try {
    var mk = findMake(A.make);
    var sd = styleData(mk, A.year);

    if (A.action === 'models') {
      return JSON.stringify({ make: mk.make_name, year: A.year, models: sd.models || [] });
    }

    var trims = (sd.trims && sd.trims[A.model]) || [];
    if (!trims.length) throw 'No trims for model "' + A.model + '" (try -a models)';

    if (A.action === 'trims') {
      return JSON.stringify({
        make: mk.make_name, year: A.year, model: A.model,
        trims: trims.map(function (t) { return { id: t.styleID, trim: t.styleDesc }; })
      });
    }

    var want = norm(A.trim);
    var style = trims.filter(function (t) { return norm(t.styleDesc) === want; })[0];
    if (!style) throw 'No trim "' + A.trim + '" in ' + A.model + ' (try -a trims)';

    var d = post('/lease-data', {
      vehicle_id: style.styleID,
      zipcode: A.zip,
      lease_term: A.term,
      miles: A.miles,
      country: 'us'
    });

    var programs = (d.programs || []).map(function (p) {
      var ld = p.lease_data || {};
      var mf = ld.mf;
      return {
        program: ld.program_name || ld.program_desc,
        delivery: ld.delivery_types,
        lender: ld.lender,
        lender_type: p.lender_type,
        mf: mf,
        apr: (mf != null) ? Math.round(mf * 2400 * 100) / 100 : null,
        rv: rvForMiles(ld, A.miles),
        rv_mileage: A.miles,
        exp_date: ld.exp_date,
        incentives: incentives(p)
      };
    });

    return JSON.stringify({
      make: mk.make_name, year: A.year, model: A.model,
      trim: style.styleDesc, vehicle_id: style.styleID,
      term: A.term, miles: A.miles, zip: A.zip,
      programs: programs
    });
  } catch (e) {
    return JSON.stringify({ err: String(e) });
  }
})()